Machines for working on surfaces by means of a driven grinding or polishing wheel are well known in different designs. These comprise for example so-called orbital sanders or eccentric sanders, with which a fixture for the actual tool, the sandpaper, is oscillated by means of an eccentric, which is rotated by a motor.
Furthermore also devices are already well known, with which several tool holding fixtures, for example in the form of discs for the mounting of grinding or polishing tools are intended, in order to cover a larger work area.
A particularly favorable device in regard to the grinding respectively polishing machining of also curved surfaces is described in DE 44 47 162 A. With this device three tool holding fixtures can be driven by a central motor and a set of gears in a triangular system for rotation around their own rotational axis, whereby the tool holding fixtures are mounted independently from each other swiveling in a ball joint-like fixture in a housing for the all-round horizontal swing of the rotational axis within a given angle range and the tool holding fixtures can be driven for rotation in each swiveling position.
A disadvantage of these existing grinding respectively polishing machines consists of the fact that the achievement of a symmetrical grinding pattern is only possible with relatively high experience, since the individual tools e.g. in the form of grinding or polishing discs of the machines machine during their rotation in each case only a certain partial surface and that for the machining of a larger connected surface the whole machine has to be moved manually by an operator over the surface to be machined. For this on the one hand an extensive symmetrical movement usually with large expenditure of force is required of the operator and on the other hand it is only possible with a high extent of experience and skill of the operator to hold the tool in symmetrical engagement and to avoid visible grinding marks or unevenness between the single working areas. Furthermore relative much time is necessary for the machining of a larger area, since the area that can be machined at the same time by such a device is limited to the sum of the single working on areas of the individual grinding or polishing discs of the machine.
Therefore it is the task of the invention to provide a device for the machining of surfaces that avoids the disadvantages described above or at least reduces them.
This task is solved by a device for the machining of surfaces in accordance with claim 1. Preferential embodiments are indicated in the sub claims.
As a result of the superposition of the rotation of the individual tool holding fixture(s) with the rotation of the housing unit, at respectively in which the tool holding fixture(s) is/are mounted, the device according to the invention enables an enlargement of the work area, a significantly better and faster machining result, and a good superposition of the grinding marks with the result of a very good and symmetrical grinding pattern with a noticeably reduced movement and without the necessity of high experience respectively skill of the operator.
Special benefits result from the application of the features according to the invention to the well-known grinding machine from DE 44 47 162 A, which possess one or several all-around swiveling rotatable tool holding fixtures. With this preferential embodiment the benefits specified above can be achieved during machining of even and curved surfaces.
Finally an expenditure of force for holding and guiding the device over the surface to be worked on is significantly reduced by neutralization of the torques, in particular with the direction of rotation moving in opposite directions of the tool holding fixture(s) on the one hand and the housing unit on the other hand.